The Experimental Study Of Condensation Heat Transfer Of Vapor Inside Vertical Tube

The experimental investigation of steam condensation inside a vertical tube was carried out in this dissertation. This in-tube condensation experiment was operated on four different condition of the inlet steam pressure(0.062MPa,0.103MPa,0.143MPa and 0.198MPa)within bare tube, corrugated tube and spiral fluted tube. The dissertation introduce a new technique of putting a helix spring insert in tube to enhance the in-tube steam condensation.The result of experimental investigations show that within the range of test, the cooling water convection heat transfer coefficient h_o and the total heat transfer coefficient k of corrugated tube and spiral fluted tube are both higher than that of the bare tube on the four different steam pressure conditions above; When entranced steam pressure is below or closed to atmospheric pressure, the using of corrugated tube and spiral fluted tube can enhance the condensation heat transfer coefficient. When entranced steam pressure is 0.103MPa, the corrugated tube's condensation heat transfer coefficient h_i increase of 10%～32% compared with that of bare tube; the spiral fluted tube's condensation heat transfer coefficient h_i increase of 11%～40% compared with that of bare tube; on the condition of high steam pressure, these two enhanced tubes' condensation heat transfer coefficient h_i is lower than that of bare tube, in the range of cooling water flow, when the entranced steam pressure is 0.143MPa, the h_i of spiral fluted tube is about 83%～90% of the bare tube's h_i;when the entranced steam pressure is 0.198MPa the corrugated tube's h_i is about 81%～84% of the bare tube's h_i.The result of the helix spring insert's enhance condensation heat transfer experimental investigation shows: when the entranced steam pressure is 0.143MPa, the h_i of tube within the helix spring insert is about 15%～25% higher than that of bare tube, but the total pressure drop is about 8.1 times of the bare tube.In the residual heat removal system, there is a problem that the temperature of the heat transfer tubes' surface is too high to beget a salt accumulating phenomenon on the tubes' surface. To resolve this problem, a new technique of introducing a tube insert is brought forward in this dissertation.